title: Sorption of selenium(IV) onto magnetite in the presence of silicic acid.
abstract: Sorption of selenium(IV) and silicic acid onto magnetite (Fe(3)O(4)) was investigated in binary systems, with concentrations of silicic acid under the solubility limit of amorphous silica. Using the double diffuse layer model (DDLM), surface complexation constants of selenium(IV) and H(4)SiO(4) onto magnetite were extracted using Fiteql 4.0. Then, prediction curves of the sorption of selenium(IV) in the presence of silicic acid onto magnetite were obtained, using the calculated surface complexation constants. Finally, laboratory experiments were performed and showed a competition between selenium(IV) and silicic acid for the surface sites of magnetite. Experimental results matched the model predictions, confirming its ability to model qualitatively and quantitatively the ternary system.
authors.affiliation: Université de Nice-Sophia-Antipolis, Laboratoire de Radiochimie, Sciences Analytiques et Environnement, 28 Avenue Valrose, 06108 Nice Cedex 2, France. jordan@unice.fr
authors.forename: Norbert
authors.initials: N
authors.lastname: Jordan
authors.forename: Claire
authors.initials: C
authors.lastname: Lomenech
authors.forename: Nicolas
authors.initials: N
authors.lastname: Marmier
authors.forename: Eric
authors.initials: E
authors.lastname: Giffaut
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Ehrhardt